The present invention relates to a kneader-mixer for the carrying out of mechanical, chemical and/or thermal processes which has at least two axial-parallel rotating shafts on each of which there are at least kneading and transport elements succeeding each other in the direction of rotation of the shafts, kneading and transport elements following each other in the axial direction of the corresponding shaft which contains a gap with respect to each other through which some of the kneading and transport element pass on the other shaft in each case.
Products must be treated today in many fields of industry, particularly however in the chemical industry. For example, in the kneader-mixer described above, two chemical products must be so intimately mixed together that they at least partially react. In this case, these products may pass through any desired aggregate state so that the requirements made on the kneader-mixer are very high.
In essence, a distinction is made between single-shaft and double-shaft kneader-mixers. The present invention concerns a multi-spindle kneader and mixing machine such as described, for instance, in CH-A 506 322. In that case, radial disk elements are present on a shaft, and axially directed kneading bars arranged between the disks. Kneading elements developed in frame shape engage between these disks from the other shaft. These kneading elements clean the disks and kneading bars of the first shaft. The kneading bars on both shafts, in their turn, clean the inner wall of the housing.
Further embodiments of multi-shaft kneader-mixers are described in EP 92 10 88 29.0.
In all of these multiple-spindle mixers and kneader-mixers it is a question, above all, of freeing all surfaces which come into contact with the product to be treated, and in particular, with the heated surfaces, from product encrustations or attachments. In the above-mentioned European Patent Application 92 10 88 29.0, this is done already to a substantial extent; to be sure, due to the gap between the kneading and transport elements, a ring which is not cleaned always remains on the inner wall of the housing both on the agitator shaft and on the cleaning shaft.
The object of the present invention is to create a possibility for also eliminating this ring.